<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<style>
    * {
        padding: 0;
        margin: 0;
    }

    .header {
        width: 100%;
        height: 100px;
        background-color: black;
    }

    .wrapper {
        padding: 0 100px;
    }

    .clearfix::after {
        content: "";
        display: block;
        clear: both;
    }

    .center {
        width: 100%;
        background-color: red;
        float: left;
    }

    .left {
        width: 100px;
        background-color: blue;
        margin-left: -100%;
        position: relative;
        left: -100px;
        float: left;
    }

    .right {
        width: 100px;
        background-color: chartreuse;
        margin-left: -100px;
        position: relative;
        right: -100px;
        float: left;
    }

    .footer {
        background-color: darkgray;
    }
</style>

<body>
    <div class="header">头部</div>
    <div class="wrapper clearfix">
        <div class="center">主区域</div>
        <div class="left">左区域</div>
        <div class="right">右区域</div>
    </div>
    <div class="footer">底部</div>
</body>

</html>